The lighting theory and structure of light-emitting diode (LED) is different from that of conventional lighting source. An LED has advantages like low power loss, long life-time, no need for warming time, and fast responsive time. Moreover, it is small, shockproof, suitable for mass production, so LEDs are widely adopted in the market. For example, LEDs can be used in optical display apparatus, laser diodes, traffic lights, data storage devices, communication devices, illumination devices, medical devices, and so on.
The conventional two dimensional array light emitting diode device 1 shown as FIGS. 1A and 1B comprises a transparent substrate 10, a plurality of light-emitting diode units 12 extending along two dimensions and closely arranged and formed on the transparent substrate 10. Every light-emitting diode unit 12 comprises one p-type semiconductor layer 121, one light-emitting layer 122, and one n-type semiconductor layer 123. Because the transparent substrate is electrically insulating, after forming the grooves by etching between the light-emitting diode units 12, each light-emitting diode unit can be insulated to each other. Then, etching part of each light-emitting diode unit 12 to the n-type semiconductor layer 123 and forming a first electrode 18 and a second electrode 16 on the exposed region of the n-type semiconductor layer 123 and the p-type semiconductor 121, respectively. Furthermore, the first electrodes 18 and the second electrodes 16 of the plurality of the light-emitting diode units 12 are selectively connected by the conductive connecting structures 19 in order to make the plurality of the light-emitting diode units 12 to electrically connect in parallel or in series. Wherein, there can be air under the conductive connecting structure 19, or an insulating layer 13 can be formed on part surfaces of the epitaxial layers of the light-emitting diode units 12 and the regions between the adjacent light-emitting diode units 12 by chemical vapor deposition method (CVD), physical vapor deposition method (PVD), or sputtering method and so on in order to protect and electrically insulate the epitaxial layers of the adjacent light-emitting diode units 12. The material of the insulating layer 13 can be aluminum oxide (Al2O3), silicon dioxide (SiO2), aluminum nitride (AlN), silicon nitride (SiNOx), titanium oxide (TiO2), and the combination thereof.
However, because the height difference between the grooves 14 and the light-emitting units 12 is large, the conductive connecting structures 19 electrically connecting the light-emitting diode units 12 is easy to cause the connecting failure and to influence the yield of the device.
Besides, the aforementioned light emitting diode device 1 can further constitute and connect with other devices to form a light-emitting apparatus 100. FIG. 11 illustrates a conventional light-emitting apparatus 100. As shown in FIG. 11, a light-emitting apparatus 100 comprises one submount 110 comprising one circuit 101 thereon; the aforementioned light-emitting diode device 1 attached on the submount 110; and an electrical connecting structure 104 electrically connecting the first electrode pad 16′ and the second electrode pad 18′ of the first light-emitting diode device 1 and the circuit 101 on the lead frame 110. Wherein, the aforementioned submount 110 can be a lead frame or a large-sized mounting substrate which is advantageous for circuit design of the light-emitting apparatus and heat dissipating. The aforementioned electrical connecting structure 104 can be the bonding wire or other connecting structures.